The shooting range of a wide-angle lens is larger than a common lens; thus, the wide-angle lens can shoot images by wider angle of view; as having large angle of view, the wide-angle lens is comprehensively applied to monitoring system or vehicle-mounted image capturing device. Currently, the demand of the wide-angle lens also keeps increasing.
However, due to the design of the wide-angle lens, the object in the image captured by the wide-angle lens may be seriously distorted; further, the geometric shape of the object in the image captured by the wide-angle lens may be incorrect due to the design of the photosensitive element of the wide-angle lens; for the above reasons, the wide-angel lens cannot correctly show the real appearance of the object in the captured image; unfortunately, the conventional field of view calibration method cannot effectively solve the above problems.